Re: Bignum speedup patch causes crash at startup

[Eli Zaretskii]

> Cc: address@hidden, address@hidden
> From: Paul Eggert <address@hidden>
> Date: Tue, 4 Sep 2018 11:59:53 -0700
> 
> First, converting a fixnum to a double can lose info.

Whether that is a possibility could be established by a simple
magnitude test.

> Second, the double 
> division could round, which would mean the result would be double-rounded. 
> We're 
> already suffering from double-rounding when either argument is 
> floating-point, 
> and we don't want that bug to also infect integer division.

I don't understand what bug you are alluding to.  Can you elaborate?

> So even the Emacs 26 code (which doesn't have bignums) must use
> integer division here, not double division.

Fine, but don't you agree that calling libgmp, when the second
argument is 1 and the 1st is a fixnum, is a little bit ridiculous?
Could we at least special-case that?

Thanks.